Research on Display Methods and Poiniting Mechanisms for Effective 3D manipulation in CAI System

我们的研究目标是提出并构建一个面向对象的基于知识的体系结构的原型，使交互学习环境(Interactive Learning Environment，ILE)研究人员或教学设计人员能够通过原型、评估和重新设计的进化过程来开发他们的系统。该系统为学生提供了一个构建块的曲目，他们可以利用这些积木来构建和操纵他们的问题的媒体表征，并与系统合作并与系统达成一致，目的是帮助学生理解问题并发现解决问题的子目标。该系统还监控学生的解题路径，当被问到时，可以将他们带回系统生成的任何真实解题方式的误区，并引导学生纠正不完整或定义不明确的问题描述，或根据他们选择的真实解题策略路径重做解题。研究集中在文字代数题、初等几何、电路分析、力学和电磁学等样本解题，其中解题情景的媒体表征起着重要作用。由此产生了一种系统设计方法论，可以继承和实例化抽象框架中定义的帮助构建和操作媒体隐喻表征的通用方法，以构建和操作最终设计者实现的子框架实例。还获得了指导学生绘制的图形符合指定条件的算法，并通过对图形的观察和混淆来提示子目标。开发了知识单元的图解应用程序。

The objective of our research has been and is to propose and construct a prototype of an object-oriented knowledgebased architecture that enables the ILE (Interactive Learning Environment) researchers or instructional designers to develop their systems by an evolutional process of prototyping, assessment and redesigning. The system provides the students with a repertoire of building blocks with which they can construct and manipulate the media representation of their problems in collaboration and "agreement" with the system, for the purpose of assisting the students to understand problems and to discover problem-solving subgoals. The system also monitors the solution paths of the students and, when asked, can bring them back to the point where they have gone astray off any of the authentic ways of solution the system can generate, and guide the students in correcting incomplete or ill- defined problem description, or redoing solution according to their choices along authentic strategy paths of problem-solving.The study has focused on such sample doamins as word algebra problems, elementary geometry, electrical circuit analysis, mechanics, and electromagnetics, in all of which the media representation of problem solving situations plays an important role. And there has resulted an methodology of system design according to which generic methods for help constructing and manipulating media metaphor representaions defined in abstract frames can be inherited and instantiated for constructing and manipulating instances of their subframes implemented by end-designers.Algorithms also have been obtained that guide the students so as the figures they draw fit the specified conditions and suggest subgoals by observation and purterbation of the figures. Programs for diagrammatical application of the knowledge units have been developed.